"MCB 252: CELL STRUCTURE AND FUNCTION
ASSESSMENT"
1. In lecture we discussed the fact that actin plays a role in phagocytosis. Based on that
discussion, do you expect that addition of latrunculin to cells would stop phagocytosis? (2pts)
A. Yes, latrunculin would stop phagocytosis.
B. No, latrunculin would not stop phagocytosis. - answers✔✔A. Yes, latrunculin would stop
phagocytosis.
2. As discussed in lecture, the contractile bundles (sarcomeres) found in muscle cells most likely
appeared in evolution before the contractile bundles found in stress fibers. (2pts)
A. TRUE
B. FALSE - answers✔✔B. FALSE
Intermediate filaments are considered equilibrium polymers, as opposed to actin filaments
which are best described as steady state filaments. (2pts)
A. TRUE
B. FALSE - answers✔✔A. TRUE
4. As described in lecture, because actin filaments are helical, any motor protein that moves
along those filaments must follow a helical path. (2pts)
A. TRUE
B. FALSE - answers✔✔B. FALSE
,5. As described in lecture, a polyclonal antibody contains many different antibodies, each of
which recognizes a distinct epitope on the surface of an antigen. (2pts)
A. TRUE
B. FALSE - answers✔✔A. TRUE
6. Profilin binds to which end of an actin monomer? (2pts)
A. The plus end
B. The minus end - answers✔✔A. The plus end
7. Exon shuffling occurs at the level of DNA in the genome; whereas, splicing occurs at the level
of RNA. (2pts)
A. TRUE
B. FALSE - answers✔✔A. TRUE
8. As described in lecture, Homo sapiens migrated out of Africa before Neanderthals migrated
out of Africa. (2pts)
A. TRUE
B. FALSE - answers✔✔B. FALSE
9. In lecture, we discussed the modular construction of some genes and the evolution of genes
(and proteins) by the addition of domains. As described in lecture, this process occurs in
prokaryotes and eukaryotes. (2pts)
A. TRUE
B. FALSE - answers✔✔B. FALSE
10. As described in lecture, all cytoskeletal polymers are multi-stranded. (2pts)
A. TRUE
B. FALSE - answers✔✔A. TRUE
, 11. Which property of eukaryotic gene regulatory regions, as discussed in lecture, allowed for
the evolution complex regulatory regions? (3pts)
A. That core promoters act over precise distances
B. That there are different types of core promoters
C. That eukaryotic genes have a regulatory promoter
D. That enhancers can act over long distances
E. Both A and B are correct. - answers✔✔D. That enhancers can act over long distances
12. Which of the following statements is/are TRUE, and which is/are FALSE?
i = The majority of different colors of fluorescent proteins used by cell biologist are all naturally
occurring proteins that were isolated from different types of aquatic organisms.
ii = As described in lecture, when purifying a protein of interest one needs an assay that is
specific for that particular protein. (3pts)
A. Both i and ii are TRUE.
B. i is TRUE, and ii is FALSE.
C. i is FALSE, and ii is TRUE.
D. Both i and ii are FALSE. - answers✔✔C. i is FALSE, and ii is TRUE.
13. Congratulations! You finally managed to build a ray gun that allows you to shrink yourself
down to the size of a molecule. Like any normal person, your first idea is to stand on top of a
formin protein. That formin protein that you are standing on is immobilized on a solid surface.
Actin monomers then start to arrive at the formin upon which you are standing. Looking down
the filament, what do you see? (3pts)
A. A steady stream of actin subunits moving towards you.
B. The minus end of the actin filament is moving away from you.
ASSESSMENT"
1. In lecture we discussed the fact that actin plays a role in phagocytosis. Based on that
discussion, do you expect that addition of latrunculin to cells would stop phagocytosis? (2pts)
A. Yes, latrunculin would stop phagocytosis.
B. No, latrunculin would not stop phagocytosis. - answers✔✔A. Yes, latrunculin would stop
phagocytosis.
2. As discussed in lecture, the contractile bundles (sarcomeres) found in muscle cells most likely
appeared in evolution before the contractile bundles found in stress fibers. (2pts)
A. TRUE
B. FALSE - answers✔✔B. FALSE
Intermediate filaments are considered equilibrium polymers, as opposed to actin filaments
which are best described as steady state filaments. (2pts)
A. TRUE
B. FALSE - answers✔✔A. TRUE
4. As described in lecture, because actin filaments are helical, any motor protein that moves
along those filaments must follow a helical path. (2pts)
A. TRUE
B. FALSE - answers✔✔B. FALSE
,5. As described in lecture, a polyclonal antibody contains many different antibodies, each of
which recognizes a distinct epitope on the surface of an antigen. (2pts)
A. TRUE
B. FALSE - answers✔✔A. TRUE
6. Profilin binds to which end of an actin monomer? (2pts)
A. The plus end
B. The minus end - answers✔✔A. The plus end
7. Exon shuffling occurs at the level of DNA in the genome; whereas, splicing occurs at the level
of RNA. (2pts)
A. TRUE
B. FALSE - answers✔✔A. TRUE
8. As described in lecture, Homo sapiens migrated out of Africa before Neanderthals migrated
out of Africa. (2pts)
A. TRUE
B. FALSE - answers✔✔B. FALSE
9. In lecture, we discussed the modular construction of some genes and the evolution of genes
(and proteins) by the addition of domains. As described in lecture, this process occurs in
prokaryotes and eukaryotes. (2pts)
A. TRUE
B. FALSE - answers✔✔B. FALSE
10. As described in lecture, all cytoskeletal polymers are multi-stranded. (2pts)
A. TRUE
B. FALSE - answers✔✔A. TRUE
, 11. Which property of eukaryotic gene regulatory regions, as discussed in lecture, allowed for
the evolution complex regulatory regions? (3pts)
A. That core promoters act over precise distances
B. That there are different types of core promoters
C. That eukaryotic genes have a regulatory promoter
D. That enhancers can act over long distances
E. Both A and B are correct. - answers✔✔D. That enhancers can act over long distances
12. Which of the following statements is/are TRUE, and which is/are FALSE?
i = The majority of different colors of fluorescent proteins used by cell biologist are all naturally
occurring proteins that were isolated from different types of aquatic organisms.
ii = As described in lecture, when purifying a protein of interest one needs an assay that is
specific for that particular protein. (3pts)
A. Both i and ii are TRUE.
B. i is TRUE, and ii is FALSE.
C. i is FALSE, and ii is TRUE.
D. Both i and ii are FALSE. - answers✔✔C. i is FALSE, and ii is TRUE.
13. Congratulations! You finally managed to build a ray gun that allows you to shrink yourself
down to the size of a molecule. Like any normal person, your first idea is to stand on top of a
formin protein. That formin protein that you are standing on is immobilized on a solid surface.
Actin monomers then start to arrive at the formin upon which you are standing. Looking down
the filament, what do you see? (3pts)
A. A steady stream of actin subunits moving towards you.
B. The minus end of the actin filament is moving away from you.
